program Ilya;

{$APPTYPE CONSOLE}

uses
  SysUtils;

var
n,i,j,a,a1,sum:integer;
begin
readln(n);
sum:=0;
if (n mod 2=1) then
 begin
  a1:=3;
  for i:=0 to ((n-3) div 2) do
   begin
      a:=a1+(i*2);
      sum:=sum+a;
   end;
 end;
if (n mod 2=0) then
  begin
    a1:=0;
    for i:=1 to (n div 2) do
      begin
        a:=a1+(i*2);
        sum:=sum+a;
      end;
   end;     
writeln(sum);
readln;
end.
 